JP2009502004A - Magnetic ROM information medium - Google Patents

Abstract

The present invention comprises an apparatus (10) comprising a layer (12) having a pattern of separated portions (14) of a magnetic material (18), wherein the magnetic material generates a corresponding pattern of a local magnetic field (2) Relates to a method of manufacturing The magnetic material (18) is composed of particles (22) dispersed in a solid substance (24). The particles are magnetically stable and substantially aligned to produce a local magnetic field (2). The method includes the following steps. That is, providing a substance (32) that has particles (22) dispersed in the substance (32), the substance (32) has a viscosity to allow the particles (22) to move in the substance (32). A process of creating a pattern of separated parts (14) of the substance (32) in the layer (12) of the device (10), an external magnetic field (50), a particle (22) of the substance (32) And applying the material (32) to substantially align in the separated portion (14) and solidifying the material (32) to obtain a solid material (24). The benefit of this method is that instead of changing the internal magnetization of the particle (22), the particle (22) is moved, typically rotated, and aligned with the externally applied (applied) magnetic field (50). That is. The solidification of the substance (32) then fixes the aligned magnetically stable particles (22) inside the solid substance (24), which results in a permanently magnetized magnetic material (18).

Description

The present invention relates to a method of manufacturing an apparatus (device) comprising a layer having a pattern of separated parts of a magnetic material that produces a corresponding pattern of a local magnetic field.
The invention further relates to an apparatus.

A continuous layer of magnetic material typically produces a macroscopic magnetic field that extends outside the continuous layer of magnetic material. In a layer with separate portions of magnetic material, each portion separates from the other separate portions inside the layer and thus creates a magnetic field that extends locally outside the separate portion layer. The separated portion may be formed, for example, by a protruding portion from a continuous layer of magnetic material, or may be, for example, an isolated portion of magnetic material inside the layer.

In a magnetic ROM information carrier, an isolated bit is a separation of magnetic material that is represented by a pattern of local magnetic field that corresponds to the pattern of the part from which the information stored on the information medium is separated. Can be formed. Such a magnetic ROM information medium is disclosed, for example, in International Publication No. WO 2004/032149. In this document, a storage device is disclosed, comprising an information medium part and a read-out part. The information medium unit includes an information plane for cooperating with the reading unit. The information plane comprises a pattern of electromagnetic material that is a component of an array of bit locations. The presence or absence of an electro-magnetic material in the information plane represents a logical value. In the first bit part, material is present, for example, indicating a logical value 1, and in the second bit part, no material is present, for example, indicating a logical value 0. In a particular embodiment of the disclosed information medium, the electromagnetic material in which bits are represented by bit sites is an isolated bit of hard magnetic material. The isolated bit pattern of hard magnetic material is permanently magnetized in an external magnetic field, creating a pattern of all magnetized magnetic bits that have substantially the same magnetic field direction with a certain magnetic field strength. The readout part comprises an electromagnetic sensor (sensor) element (element), which is sensitive to the presence of the electromagnetic material. Reading is performed via resistance measurements that depend on the magnetoresistance phenomenon. The resistance in the sensor element is influenced by the nearby magnetic field. In the bit part of the information medium part where the magnetized bit exists, the magnetic bit substantially provides a magnetic field having a magnetic field direction and a magnetic field strength for the sensor element, resulting in a first sensed resistance. . In the bit part of the information medium part where the magnetic bit is not present, the sensor element senses a different magnetic field strength, leading to a second sensing resistor, which is different from the first sensing resistor. When the resistance of the sensor element is measured at each of the bit portions, the respective logical value of the bit portion can be determined.

An obstacle to known read-only (dedicated) magnetic information media is that the pattern of hard magnetic material must be magnetized during manufacture, which typically requires a strong magnetic field.

It is an object of the present invention to provide a method of manufacturing an apparatus comprising a pattern of magnetic material that can be magnetized relatively easily.

According to a first aspect of the present invention, this object is achieved using a method of manufacturing a device as defined in the beginning, wherein the magnetic material is composed of particles dispersed in a solid substance, the particles being Magnetically stable and substantially aligned to produce a local magnetic field, the method comprises the following steps. That is, a process that provides a substance, has particles dispersed in that substance, and has a viscosity to allow the substance to move in the substance, creating a pattern of separated parts of the substance in the layer of the device Applying an external magnetic field to substantially align the particles in the separated portions of the material, and solidifying the material to obtain a solid material.

A magnetic material is composed of substantially isolated particles that spread in the material. Each particle produces an aligned particle magnetic field. For alignment, the particle magnetic field of the particles inside the separated part is added up to produce a local magnetic field that exits the separated part. The particles are magnetically stable, which ensures the direction of magnetization within the particles and prevents random changes in the magnetization direction of the particles. The solidification of the material ensures that the particles maintain the alignment of the particles inside (inside) the separated parts.

The effect of the measures according to the invention is that the applied material has a viscosity that allows movement of particles dispersed in the material. In the manufacturing method, the particles are aligned using an external magnetic field. Due to the ability of the particles to move within the material, only a relatively weak externally applied magnetic field is required, the particles are moved mechanically, and the particles are aligned within the substrate. . The solidification of the substance then fixes the aligned magnetically stable particles within the solid substance, resulting in a magnetic material that is permanently magnetized. Instead of changes, the magnetization of particles requires a relatively strong externally applied magnetic field, and the particles move mechanically inside the material, which translates into their relatively good mobility. Due to and for example, the particle magnetic field rotates to align with the externally applied magnetic field. The strength of the externally applied magnetic field achieves particle alignment and typically depends on the mobility of the particles inside the material.

The mechanical movement of the particles typically comprises rotation of the particles due to the externally applied magnetic field and aligns the particles with respect to the externally applied magnetic field. In a specific example, the externally applied magnetic field comprises a magnetic field gradient, but the mechanical movement also comprises the movement of particles along the gradient.

The applied material can be, for example, a solid material that is hot melted to obtain increased mobility of the particles during magnetization and then cooled to fix the aligned particles in the solid material. Alternatively, the chemical composition of the material can be changed after magnetization, eg, polymerization of the magnetizing monomeric material, to obtain a solid polymer.

An additional benefit of the method of manufacture according to the present invention is that the method of manufacture allows the use of well-known manufacturing processes to create separate part patterns. The required viscosity of a material is typically embossing or stamping to create a discrete pattern in the layer to allow the particles to move in the material. Allow the use of such manufacturing processes.

The present invention is based on the recognition that the stability of magnetic particles depends on the barrier energy. The barrier energy defines, for example, the energy level that must be overcome in order to change the magnetization direction of the magnetic bit using an external magnetic field. The barrier energy typically depends on the capacity of the magnetic particles and on the magnetic anisotropy energy density of the magnetic particles. Reducing the volume of magnetic particles also reduces the barrier energy. As the barrier energy approaches the thermal energy of the material, the magnetization direction of the magnetic particles becomes unstable, which leads to a random change in the magnetization direction of the magnetic particles. Application of magnetic particles composed of a magnetic material with a relatively high magnetic anisotropy energy density increases the stability of the magnetic particles, but also to set a relatively strong magnetic field to set the magnetization direction, Required inside the magnetic particle. In the method of manufacturing the device according to the invention, the magnetic material is magnetized, which is by mechanically aligning the magnetically stable particles dispersed in the material, rather than by changing the magnetization direction inside the particles. It is. When the mobility of the magnetic particles is high, a material with a high magnetic anisotropy energy density can be applied in the particles, while an externally applied magnetic field that is still relatively weak is sufficient for magnetization.

According to a second aspect of the present invention, the object is achieved using an apparatus as defined in the beginning, wherein the magnetic material is composed of particles dispersed in a solid substance, the particles being magnetically Stable and substantially aligned to produce a local magnetic field. A magnetic material composed of particles dispersed in a solid material is typically easier to manufacture and process than a conventional magnetic material, which makes a magnetic device according to the present invention typically a conventional Less expensive than a simple magnetic device.

In an embodiment of the method, the step of applying an external magnetic field is performed during the step of solidifying the material. The benefit of this embodiment is that an external magnetic field is present during solidification, so that the particles remain aligned during solidification of the material, which optimizes the contribution of each particle magnetic field to the local magnetic field pattern. Is to make sure.

In an embodiment of the method, applying the external magnetic field comprises creating a spatial magnetic field strength variation in the external magnetic field. Due to spatial magnetic field strength fluctuations, the magnetic field may be concentrated, for example, in separated portions. This allows a further reduction in the overall field strength of the externally applied magnetic field, while maintaining a sufficiently strong magnetic field to align the particles in separate parts.

In an embodiment of the method, the step of applying an external magnetic field is performed during the step of creating a pattern of separated portions, wherein the step of creating the pattern of separated portions is the pattern of the separated portions. The method comprises the step of utilizing a mark for creation, the mark comprising a magnetically permeable material in order to create a spatial magnetic field strength variation. A magnetically permeable material collects magnetic field lines. When magnetically permeable material is brought about in a uniform magnetic field, the gathering of magnetic field lines introduces an increased concentration of magnetic field lines in the magnetically permeable material, and spatial field strength fluctuations are introduced. Create.

In a method embodiment, the magnetically permeable material of the indicia is arranged in an indicia-pattern corresponding to the pattern of separated portions. The benefit of this embodiment is that when an external magnetic field is applied while the mark creates a pattern of separated parts, the magnetically permeable material collects the magnetic field lines and the space corresponding to the separated part pattern Creating a magnetic field strength fluctuation, increasing the magnetic field strength in the separated part, and reducing the magnetic field strength outside (outside) the separated part. Next to enabling a reduction in the overall field strength of the externally applied magnetic field, these field strength variations typically result in magnetic field gradients that cause particle migration and particle concentration differences. The result is along the gradient created in the material. Magnetized particles tend to maximize their magnetic flux and move to regions where the magnetic field is stronger, based on the mobility of the particles. Differences in the concentration of particles in the device lead to differences in the magnetic field strength of the local magnetic field. After particle fixation and removal of the external magnetic field, particle concentration fluctuations cause field-intensity fluctuations of the local magnetic field in the device.

In an embodiment of the method, the magnetically permeable material of the indicia is aligned in a protruding portion that exits the indicia and in a negative indicia-pattern to create a pattern of separate portions. A shadow mark-pattern is a pattern of protrusions that emerges from a mark, which when applied to a material creates a pattern of separate parts in the material. The benefit of this embodiment is that when applying an external magnetic field, while creating a pattern of parts where the marks are separated, the magnetically permeable material in the protruding part creates a spatial magnetic field strength variation, And concentrating the external magnetic field in separate layers. Also in this embodiment, the movement of particles towards the separated part can occur, which depends on the mobility of the particles dispersed in the substance.

In an embodiment of the method, providing the material comprises providing the material in a continuous layer, and wherein creating the separated portion pattern includes projecting portions from the continuous layer. A projecting step is provided, and the protruding portion is a separated portion. The benefit of this embodiment is that the pattern of material and separated parts can be applied relatively easily. The material can be applied, for example, by spin-coating, and the pattern can then be applied via foil stamping of the pattern, creating a pattern of protrusions from the continuous layer.

In an apparatus embodiment, the particles are composed of a material having a magnetic anisotropy energy density of at least 100 kilojoules per cubic meter, and preferably above 400 kilojoules per cubic meter. The barrier energy associated with particles composed of materials with a magnetic anisotropy energy density higher than 100 kilojoules per cubic meter typically remains large, comparing the magnetic stability of the magnetization direction of the particles. It seems to be enough to ensure even small dimensions of particles. A material with a magnetic anisotropy energy density higher than 400 kilojoules per cubic meter allows for further reduction in particle size. Although these materials are very difficult to magnetize, the proposed device allows the magnetization of the particles using a relatively weak externally applied magnetic field.

In the device embodiment, the local magnetic fields all have substantially the same magnetic field direction. The separated pattern of magnetic material typically comprises a pattern of magnetic field strength variation that can be sensed by a sensor. The pattern of magnetic field strength variation can represent, for example, information stored on the device.

In an embodiment of the device, the solid material is a polymer. An advantage when using polymers is that a wide range of manufacturing methods well known to the skilled person can be employed. A further benefit when using polymers is that the polymers are typically produced from monomers with low viscosity. Particles suspended in the monomer typically move relatively freely and can therefore be aligned using a relatively weak external magnetic field. Subsequent polymerization of the monomer preferably results in a permanently magnetized polymer in the presence of an externally applied magnetic field.

These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter. The description relating to the drawings will be transferred to the section (Brief description of the drawings).

 The drawings are purely schematic and are not drawn to scale. Some dimensions are strongly emphasized, especially for clarity. Similar components are denoted by the same reference numerals as much as possible in the drawings.

1A to 1C show specific examples of devices 10, 20, 30 according to the present invention. In the embodiment shown in FIGS. 1A-1C, the apparatus 10, 20, 30 comprises a magnetic material 18, where the magnetic material 18 is composed of particles 22 dispersed in a solid material 24. The devices 10, 20, 30 comprise a layer 12 with a separated portion 14 of magnetic material 18. The particles 22 in the solid material 24 are magnetized particles 22 that are magnetized in the direction indicated by the arrows inside the particles 22. In the embodiment shown, the particles 22 are substantially aligned using, for example, an externally applied magnetic field 50, 52 (see FIGS. 2C, 2D, 3B and 3E). Due to the aligned and magnetized particles 22, the magnetic material 18 comprises a macroscopic (relatively weak) magnetic field 4. Within the layer 12, the separated portion 14 is an isolated portion of the magnetized material 18 that produces a local (relatively strong) magnetic field 2 that exits the device 10, 20, 30.

In a specific example of the devices 10, 20, 30 the devices 10, 20, 30 are, for example, magnetic readings representing the information in which the pattern of the local magnetic field 2 is stored on a magnetic read only memory (Read Only Memory) device. It is a dedicated memory device. Each separate portion 14 may represent the value of the magnetic bit, where the presence or absence of the separate portion 14 that produces the local magnetic field 2 may represent the value of the magnetic bit. In a further embodiment, the device 10, 20, 30 is, for example, a part of an array of biosensors requiring a local magnetic field 2 pattern.

The magnetic material 18 comprises particles 22 dispersed in a solid material 24. The solid material 24 may be a non-permeable material for causing the magnetic field of the particles to lead to and create a local magnetic field that exits the separated portion 14. In a preferred embodiment, the solid material 24 is a polymer that allows the devices 10, 20, 30 to be manufactured through the use of a wide range of well-known production methods.

The particles 22 are dispersed in the solid material 24 and are magnetically stable. Typically, the magnetic stability is determined by the barrier energy, which is the energy required to change the magnetization direction of the particle 22. The barrier energy depends on the capacity of the particles 22 and on a material variable called magnetic anisotropy energy density. It can be readily appreciated that the reduction in the size of the particles 22 allows the device 10, 20, 30 to reduce the size of the separated portion 14. In particular, when the device 10, 20, 30 is used as a read-only memory device, the reduced size of the isolated portion 14 allows for an increase in the storage density of the device 10, 20, 30. However, reducing the size of the particles 22 reduces the barrier energy, and when the barrier energy approaches the thermal energy of the particles 22, they become magnetically unstable and randomly change the magnetization. The particles 22 are composed of a material with a high magnetic anisotropy energy density, for example, a magnetic anisotropy energy density higher than 100 kilojoules per cubic meter reduces the particle size to less than 13 nanometers. While enabling the particles 22 to retain their magnetic stability for thousands of years. In a preferred embodiment, the particles 22 were composed of a material with a magnetic anisotropy energy density higher than 400 kilojoules per cubic meter, for example, the particles 22 were composed of samarium cobalt (SmCo). The use of samarium cobalt allows the particle 22 size to be reduced to less than 8.5 cubic nanometers while maintaining magnetic stability for hundreds of years. The magnetic material 18 comprises samarium cobalt as particles 22 dispersed in the solid material 24, allowing separate portions 14 with sub-micron dimensions that result in a typical storage capacity of 100 gigabits per square inch.

Due to the alignment of the particles 22, the magnetic material 18 is magnetized. In order to obtain a magnetic material 18 that is substantially permanently magnetized, the magnetization direction of the particles 22 dispersed in the solid material 24 must be fixed within the solid material 24. To achieve this, the particles 22 are chosen to be magnetically stable (see previous paragraph). However, the magnetic stability of the magnetic material 18 also depends on the fixation of the particles 22 in the solid material 24. For example, when the particles 22 are spherical, rotation of the particles 22 in the solid material 24 may still be possible. In the embodiment of the device 10, 20, 30, the particles 22 have a shape to ensure the alignment of the particles 22 within the solid material 24. In a further embodiment of the device 10, 20, 30, the particles 22 are chemically bonded to the solid material 24 to ensure alignment of the particles 22 within the solid material 24. Fixing the alignment of the particles 22 in the solid material 24 ensures the magnetization of the magnetic material 18 and the pattern of the local magnetic field 2 of the devices 10, 20, 30.

FIG. 1A shows an embodiment of the device 10 in which the magnetic material 18 is provided in a continuous layer 28, and the separated portion 14 is constituted by a protruding portion 14 from the continuous layer 28.

FIG. 1B shows an embodiment of the device 20 in which an additional cover layer 34 is applied and the layer 12 of the separated portion 14 is covered. The cover layer 34 is composed of, for example, a non-magnetic material that allows the local magnetic field 2 to leave the device 20.

FIG. 1C shows a specific example of an apparatus 30 in which the pattern of separated portions 14 is applied directly to the substrate 26. The pattern of separated portions 14 can be applied, for example, via drops of liquid magnetic material 18 where the particles 22 can be aligned. Subsequent solidification of the drop of magnetic material 18 results in a pattern of separated portions 14 of particles 22 dispersed in solid material 24.

FIGS. 2A to 2E show several steps (several, about 5 or 6) of the method of manufacturing the device 10 according to the present invention.

FIG. 2A shows that a layer 28 of magnetic material 18 is applied to substrate 26, where magnetic material 18 is composed of particles 22 dispersed in substance 32. The material 32 typically has a viscosity that allows the particles 22 dispersed in the material 32 to rotate relatively freely. FIG. 2A also shows the mark 40 with a protruding portion 42 that exits the mark 40. The protruding portions 42 from the mark 40 are arranged in a shadow mark-pattern. The shadow mark-pattern is chosen such that when the mark 40 is applied to the layer 28 of the magnetic material 18, a pattern of separate portions 14 is created in the magnetic material 18. The viscosity of the substance 32 that allows the dispersed particles 22 in the substance 32 to rotate typically also allows the creation of a pattern of separated portions 14 by applying indicia 40 in the layer 28 of the magnetic material 18. .

FIG. 2B shows indicia 40 applied to layer 28 of magnetic material 18 to create layer 12 with a pattern of separated portions 14.

FIG. 2C shows the alignment of the particles 22 dispersed in the substance 32 via an externally applied magnetic field 50. The applied mark 40 is composed of, for example, a non-permeable material to allow an externally applied magnetic field 50 to align the particles 22 dispersed in the material 32. In a specific example, indicia 40 is composed of a magnetized permanent magnetic material and provides a local applied field pattern for layer 28 of magnetic material 18. In FIG. 2C, the externally applied magnetic field 50 is aligned parallel to the layer 28. The externally applied magnetic field 50 can also be aligned perpendicular to the layer 28 or at a predetermined angle with respect to the layer 28 without departing from the scope of the present invention.

FIG. 2D shows the solidification process of material 32 to obtain solid material 24. Solidification as shown in FIG. 2D is performed by irradiating material 32 with ultraviolet light UV through indicia 40, for example, changing the chemical composition of material 32. The substance 32 is, for example, a monomer and polymerizes when irradiated with ultraviolet light UV to form a solid substance 24 that is a polymer. Solidification of the substance 32 fixes the magnetically aligned particles 22 in the solid substance 24 and creates a magnetic material 18 that is permanently magnetized. Alternatively, the material 32 may be a solid material 24 that is hot melted, and increased mobility of the particles 22 can be obtained during application of the indicia 40 and during alignment of the particles 22. Cooling then ensures a pattern of separated portions 14 in the magnetic material 18 and aligns particles 22 in the solid material 24. An additional benefit when using material 32 with an elevated temperature is that an increase in temperature avoids clustering of particles 22 by enhanced thermal agitation.

FIG. 2E shows the apparatus 10 as produced according to the process steps shown. As the separated portion 14 protrudes from the continuous layer 28 of magnetic material 18, a local magnetic field 2 is created.

Modifications to the steps shown in FIGS. 2A through 2E may be performed without departing from the scope of the present invention. For example, the externally applied magnetic field may be present during any one of the steps shown in FIGS. 2A to 2D. In particular, applying an externally applied magnetic field 50 during the solidification process ensures the alignment of the particles 22 during the solidification process. Another modification may be to remove the mark 40 before the substance 32 solidifies. The magnetic material 18 has a viscosity, for example, such that the pattern of separated portions 14 remains in the layer 12 even when the indicia 40 is removed. The benefit of this modification is that the indicia 40 need not be transparent for ultraviolet light UV. Modifications in the solidification process can be solidified, for example, via oxidation, two-component blending, thermosetting, or cooling without departing from the scope of the present invention. The type of coagulation depends on the substance 32 used.

In the embodiment shown in FIGS. 2C to 2E, all particles 22 in the magnetic material 18 are substantially aligned. In an alternative embodiment (not shown), the alignment of the particles 22 may be one of a plurality of predetermined magnetic field directions, for example, in the separated portion 14. This can be achieved by locally reducing the viscosity of the solid material 24, for example by applying a local heating of the solid material 24 and an external magnetic field 50 corresponding to the required local magnetic field direction. . Then, the local magnetic field direction of the separated portion 14 is secured by increasing the viscosity, for example, cooling the solid material 24. Alternatively, the predetermined magnetic field directions can be achieved by local coagulation. For example, a first mask (not shown) is applied between the ultraviolet light UV and the magnetic material 18 that transmits the ultraviolet light UV only in a predetermined separate portion 14, while the first There is an externally applied magnetic field (not shown). A second mask (not shown) replaces the first mask and transmits UV light UV only in the alternative separate portion 14, while a second external applied magnetic field (not shown) Exists. The magnetization direction of the first externally applied magnetic field is different from the magnetization direction of the second externally applied magnetic field. A pattern of the local magnetic field 2 comprising a plurality of predetermined magnetic field directions can be sensed using a sensor that is sensitive to differences in the magnetic field direction. When a device with a plurality of predetermined magnetic field directions is used as a read-only memory device, the particular magnetic field direction sensed by the sensor may represent a particular value of information stored on the device.

In an alternative embodiment of the method of manufacturing the device 10, the step of solidifying the material 32 comprising the aligning particles 22 is performed before the step of creating a pattern of separated portions 14. The pattern of the separated portion 14 is, for example, a protruding portion from the solid material 24, for example, created through etching of the solid material 24. Typical etching of the solid material 24 can be performed via the well-known lithography method in which a resist can be applied to the solid material 24. Creation For example, a resist-pattern that corresponds to the required pattern of the separated portion 14 allows the etching of the solid material 24 to obtain a pattern of the separated portion 14.

FIGS. 3A through 3D illustrate the use of indicia 48, 49 for manufacturing a device in which indicia 48, 49 comprises a pattern of magnetically permeable material 44,46. The magnetically permeable material 44, 46 typically collects magnetic field lines. Applying magnetically permeable material 44, 46 in the pattern creates spatial magnetic field strength variations 54, 56. The pattern of the permeable material 44, 46 within the externally applied magnetic field 50, 52 allows for concentration of the magnetic field, for example, in the isolated portion 14. When the magnetic fields 50, 52 are concentrated in the separated part 14, the magnetic field strength of the externally applied magnetic field 50, 52 may be reduced, while still in the separated part 14, It is sufficient to align the particles 22 in the separated portions 14. An additional benefit of concentrating the externally applied magnetic fields 50, 52 in the separated portion 14 is that this allows concentration variation of the particles 22 in the magnetic material 18. The magnetized particles 22 tend to minimize their magneto-static energy, and therefore draw toward the separated portions 14 of the concentrated magnetic fields 54,56. When the magnetized particle 22 is highly mobile, the sufficient concentration in the separated part 14 of the magnetic field 54, 56 increases the density at the edges of the separated part 14 of the magnetized particle 22, resulting in Increase the strength of the local magnetic field 2 to be generated.

FIG. 3A shows the creation of a pattern of isolated portions 14 where indicia 48 is used to have a pattern of magnetically permeable material 44 corresponding to the pattern of isolated portions 14. FIG. 3B shows a spatial magnetic field strength variation 54 due to the pattern of transmissive material 44 that occurs when an external magnetic field 52 is applied (in FIG. 3B, indicia 48 indicates a spatial field strength variation 54. To decrease in height). As can be seen from FIG. 3B, an increase in the concentration of the particles 22 is shown in the separated portion 14 and is caused by the movement of the particles 22 due to the concentrated field strength variation 54. Preferably, the dimension of the transmissive material 44 perpendicular to the layer 28 should be greater than the dimension of the transmissive material 44 parallel to the layer 28.

FIG. 3C shows the creation of a pattern of isolated portions 14 where indicia 49 are used and have a permeable material 46 lined up with protruding portions 42 exiting from indicia 49. In the embodiment of indicia 49, the protruding portion 42 can be sufficiently formed from the permeable material 46. FIG. 3D shows a spatial magnetic field strength variation 56 due to the pattern of transmissive material 46, which occurs when an external magnetic field 50 is applied. In this embodiment, the spatial magnetic field strength variation 56 concentrates the externally applied magnetic field 50 in the layer 12 with the separated portion 14 and increases the strength of the magnetic field in the separated portion 14. As shown in FIG. 3D, the presence of a concentrated magnetic field compares the increased concentration of the particles 22 in the layer 12 with the separated portion 14 with the remainder of the magnetic material 18 in the separated portion 14 in the substrate 32. And create.

In an alternative embodiment, the pattern of transmissive material 44, 46 may be applied separately from indicia 48, 49, for example, a mask composed of a non-transmissive material having a pattern of transmissive material 44, 46. (Not shown) is used. A mask of transmissive material 44, 46 may be applied during the process of aligning the particles 22, for example after the indicia 40 has been applied to create a pattern of separated portions 14.

4A and 4B show two specific examples of a storage device according to the present invention. FIG. 4A shows a storage device 100 comprising a read-only magnetic information medium 10 and a device 10 that is a reading part (part) 102. The reading unit 102 includes a sensor 104, a scanning system 106, and an input / output device 108. The reading unit 102 is, for example, a motor for rotating the read-only magnetic information medium 10 across the sensor 104, or a cross (rail) 106, for example, for the sensor 104 to scan across the read-only magnetic information medium 10, or For example, a read-only magnetic information medium comprises a rung for scanning across the sensor 104. The sensor 104 senses, for example, the local magnetic field 2 of the separated portion 14 through a magneto-resistance phenomenon where the local magnetic field 2 defines a resistance at the sensor 104. The sensor 104 moves, for example, along the scanning system 106 and senses the presence or absence of the local magnetic field 2 by scanning across a separate portion 14 of the read-only magnetic information medium 10. The sensor 104 may also be sensitive to the direction of the local magnetic field 2, for example. In the example shown in FIG. 4A, the scanning system 106 is also used to provide data retrieved by the sensor 104 to the input / output device 108. Data read from the read-only magnetic information medium 10 via the input / output device 108 is provided to any other electronic equipment, such as personal computers, video games, mobile phones, etc. be able to.

FIG. 4B shows a storage device 120 according to the present invention, which is a hard disk drive 120. The hard disk drive 120 includes a plurality of storage platters 122 for storing information and a plurality of arms 126, each of which includes a read / write head 124. The hard disk drive 120 comprises a device 10 according to the invention and is a read-only magnetic information medium 10. Since the information stored on the device 10 is represented by the pattern of the local magnetic field 2, the information can be read by the read-write head 124 of the hard disk drive 120.

The above-described embodiments illustrate rather than limit the invention, and those skilled in the art will be able to design a number of alternative embodiments without departing from the scope of the appended claims. It should be noted that what can be done.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claimed invention. Use of the verb “comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a (a)” or “an” preceding an element does not exclude the presence of a plurality of such elements. The present invention can be implemented using hardware comprising several separate elements. In the invention of the device claim enumerating several means, several of these means can be embodied by one and the same item of hardware (item). The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

1A to 1C show specific examples of the device according to the present invention. 2A to 2E show several steps in the method of manufacturing the device according to the invention. 3A to 3D show the use of indicia with permeable material in the method of manufacturing the device. 4A and 4B show two specific examples of the storage device according to the present invention.

Claims (14)

A device that has a layer with a pattern of separated parts of a magnetic material, where the magnetic material generates a local magnetic field of the corresponding pattern. , And a method of manufacturing what is substantially aligned to produce a local magnetic field, comprising the following steps:
-Providing a substance, which has particles dispersed in the substance, the substance having a viscosity to allow the particles to move in the substance;
-Creating a pattern of separated parts of the material in the layer of the device,
Applying an external magnetic field to substantially align the particles in separate parts of the material,
A method comprising solidifying the substance to obtain a solid substance. The method of manufacturing an apparatus according to claim 1, wherein the step of applying an external magnetic field is performed during the step of solidifying the substance. The method of manufacturing an apparatus according to claim 1 or 2, wherein the step of applying an external magnetic field comprises the step of creating a spatial magnetic field strength variation in the external magnetic field. The step of applying an external magnetic field is performed during the process of creating a pattern of separated parts, and the step of creating the pattern of separated parts is then performed by applying a stamp to the pattern of separated parts. 4. A method of manufacturing an apparatus according to claim 3, comprising the step of utilizing to create, wherein the indicia comprises a magnetically permeable material to create a spatial magnetic field strength variation. 5. The method of manufacturing an apparatus according to claim 4, wherein the magnetically permeable material of the mark is arranged in a mark-pattern corresponding to the pattern of the separated portions. 5. A method of manufacturing an apparatus according to claim 4, wherein the magnetically permeable material of the mark is aligned at the protruding portion exiting from the mark and aligned to create a pattern of separate portions in the shadow mark-pattern. Providing a material comprises providing the material in successive layers, and creating a pattern of separated portions comprises creating a protruding portion from the continuous layer, wherein the protruding portion is 3. A method of manufacturing a device according to claim 1 or 2, wherein the device is a separated part. 3. The apparatus according to claim 1 or 2, wherein the step of providing a substance comprises the step of providing a monomer as the substance, and the step of solidifying the substance comprises the step of polymerizing the monomer to obtain a polymer. How to manufacture. A device that has a layer with a pattern of separated portions of magnetic material, where the magnetic material generates a local magnetic field of the corresponding pattern, the magnetic material is composed of particles dispersed in a solid material, and the particles are magnetically stable And substantially aligned to produce a local magnetic field. 10. The apparatus of claim 9, wherein the apparatus is a read-only magnetic information medium, wherein the local magnetic field pattern represents information stored on the read-only magnetic information medium. 11. An apparatus according to claim 9 or 10, wherein the particles are composed of a material having a magnetic anisotropy energy density of at least 100 kilojoules per cubic meter, and preferably greater than 400 kilojoules per cubic meter. 11. A device according to claim 9 or 10, wherein the local magnetic fields all have substantially the same magnetic field direction. The apparatus according to claim 9 or 10, wherein the solid substance is a polymer. 10. The apparatus according to claim 9, further comprising a reading unit, wherein the reading unit is a storage device including a sensor for sensing a local magnetic field pattern.

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